Expansion joints made of copper, with welded ends Construction: Sturdy connecting ends are welded (using inert gas) to a pack of thin plates. Material: Thin plates made of electrolytic Cu 0.2 mm thick, width 2 mm smaller than specified (38 mm, 48 mm etc.), ends made of electrolytic Cu flat material. Drill holes: Standard type undrilled, drill holes on request according to specification or DIN 43 67 Specially made types: Other forms and dimensions as the customer desires.Pressure-welded copper band on request.